Kailric
Jack of All Trades
Here are my suggestions:
Maybe, instead of just keeping the Pope happy (the Charlemagne mod was too easy) you can constantly fight the Pope over such issues as investiture (the right to appoint Bishops over districts) or marriages/divorces (much like King Henry VIII), or even appoint an "anti-Pope" and declare the Papal Pope to be a false Pope!
This is only just a recipe for more fun, because if you do that then every other state that follows the Pope will almost instantly declare war. Your civilization could also harbor a Great Prophet, Martin Luther, and your civ could be the first Protestant civ, thereby starting the Thirty Years War.
You could also attempt to make an Archbishop of yours a Cardinal and place him to the College of Cardinals, the clerical body from which the Pope was originally elected from. In this way, if your Cardinal within the College of Cardinals gets elected as Pope, it will be extremely beneficial to you as he will favor you and your civ over other civs.
And, as a further option, you could request the Pope for a Crusade against the Holy Land and colonize the Holy Land [Palestine] by creating Crusader states, which will function much like Overseas Colonies in Vanilla Civ. Or you could start your civ as a Crusader State.
These are all just suggestions, but I think that, if implemented, they will work (and they'll be pretty fun)!
However, I do like your idea for discovering the New World as a victory option, and building an Expedition sounds pretty cool. But what will the various parts of the Expedition be? You will have to include a sort of "Stasis Chamber" and all the other parts that make up the Expedition/"Spaceship".
I have released the first version of this mod and its fairly huge, over 1 GB unzipped. You can check it out at the below link....
http://forums.civfanatics.com/showthread.php?t=407186
In reply to your suggestions they are all good ideas. Right now I haven't changed up much between the Pope/Caliph and what the King did but I do plan on adding new options for the Popes. The Pope can force his own ideals on your Kingdom such as you say the right of investiture and things such as banning the use of the Crossbow which one pope did. In place of the "Boston Tea Party" there could be several options the Pope has to punish would be kings such as.. Excommunication, Interdict, Anathema, or even call a Crusade against you.
We could easly incorparate the ideas of the war of Religions and declareing your own "anti-pope" into the new Conquest system.
I like the idea of College of Cardinals and having your own Cardinal elected as Pope. Not sure exactly how to incorparate this into the current game though. Each Civ in the game at the moment has their own Conquest they must complete and I somewhat based the Conquests on actualy Historical events. Like Byzantine must withstand the Ottoman Threat and the Arabs must withstand the Crusaders.
I love history and thats one reason I love the Civ4 games so much as they take you through History. So I would love to incorparate all the Major events of the time period into the game in some form or fashion.
I especially like your plans to add more features for the King/Pope (issuing missions, banning techs, etc.)
), so yeah, any spelling corrections would be apprieciated. I added lots of text so make notes of any thing you see and post it and I'll fix it. I'll be posting an update soon and will add your corrections.